The decision ended speculation about Lotus's 2007 world champion Kimi Raikkonen moving to the team, as well as wilder talk that Ferrari's Fernando Alonsocould be in line for a switch.

The focus will now be on Felipe Massa at Ferrari, and whether the Brazilian can keep his seat, and Raikkonen's future with Lotus keen to retain him.

"It's great to confirm Daniel as the driver replacing Mark Webber. He's a product of the Red Bull Junior programme," Horner said. "He's really deserved this graduation on merit. He's a talented youngster, he's committed, he's got a great attitude and in the end it was a very logical choice for us to nominate him as a second driver.

"He's got all the attributes that are required to drive for our team: he's got a great natural ability, he's a good personality and a great guy to work with. Daniel knows what the team expects from him.

"The thing that gave Daniel the edge over the other drivers was the potential; the potential of what he can be. We've seen in his junior career in Formula 3 and Renault World Series that he's capable of winning championships, he's capable of winning races.

"He's been a stand-out driver in each of the categories he's competed in and indeed we followed his progress with great interest with Toro Rosso and some of the testing that he's done for Infiniti Red Bull Racing.

"He's got all the attributes that are required and I think that yes there's drivers that have obviously great achievements under their belts but if you don't give somebody the chance how are they going to get those achievements? We've taken a good look at what would be the right lineup and we've come to the clear conclusion that Daniel is the right guy."

Ricciardo, who was Red Bull reserve in 2010, is currently with Red Bull's sister team Toro Rosso and is 14th in the championship after 11 races with 12 points.

The seat became available after 37-year-old Webber announced in June that he would be leaving Formula One to race for Porsche in their Le Mans sportscar programme.

Webber had already told reporters at last month's Belgian Grand Prix that Ricciardo had got the job, although Horner denied a decision had been made, and confirmation came as no real surprise.

Horner said Red Bull, who have won the last three drivers' and constructors' titles and are on course to win both again this season, were taking a "medium to long-term view" in Ricciardo's development.

The Perth-born Australian, the driver with the biggest smile in the paddock even without Monday's announcement, made his excitement evident.

"When I started back in 2011 I hoped this would one day happen but I knew it was not going to be easy," Ricciardo said. "It's been a steady process that I've had to try and develop myself as well over time and to work up to this level.

"So it definitely wasn't easy getting into F1 and it's not all, you know, it's not simple but I think I definitely hoped it would happen and now over time the belief has come, had some results and obviously Red Bull have decided that this is it so it's a good time.

"I think for sure I'm going to have to put with a little bit more next year with scrutiny or whatever gets thrown my way and with a world championship winning team, you know, we'll see what's happening this year but at least for the last few years so I'm arguably with the best team and you're expected to deliver.

"We'll see; obviously I'm ready for that and I'm not here to run around 10th place, I obviously want to get results for myself and obviously for the team so we'll see what happens I'll cross that bridge when it comes but obviously ready and prepared for a little bit more attention."

"My team mate will be Sebastian Vettel and he has achieved a hell of a lot in his career so to put myself up against him I think is a great challenge for me. I'll learn, I'm sure very quickly.

"For me, I want to be put against the best and for my personal challenge as well and really see if I can mix it up with Seb and the top guys in the world so definitely looking forward to that. I know it is going to be a challenge but no better guy to have as my team mate."

Red Bull had narrowed the choice down to Raikkonen and Ricciardo but they triggered speculation by delaying any announcement even after the Finn's manager had said his driver would not be racing for Red Bull.

Horner told reporters in Spa that the team wanted time because Webber's were big shoes to fill and some other surprising candidates had emerged.